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dpaddy
Tux's lil' helper
Joined: 25 Jun 2008
Posts: 142
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 Posted: Thu Sep 03, 2020 6:56 pm Post subject: [SOLVED] potential grub2 i386-pc problems ??? |
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I am trying to build a new system (AB350M Pro4 motherboard) using a disk which I do not want to reformat, but would like to install GRUB2.
| Code: | livecd ~ # parted /dev/sda
GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) unit mib
unit mib
(parted) print
print
Model: ATA WDC WD1005FBYZ-0 (scsi)
Disk /dev/sda: 953870MiB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1.00MiB 9.00MiB 8.00MiB grub bios_grub
2 9.00MiB 1027MiB 1018MiB ext2 boot boot, esp
3 1027MiB 33795MiB 32768MiB linux-swap(v1) swap
4 33795MiB 953869MiB 920074MiB ext4 rootfs
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I have a number of issues...
First, whereas I think there are both "PC BIOS" and "64-bit UEFI" options for the "GRUB_PLATFORM" (I am x86_64 AMD Ryzen 7 1800X) my muddled understanding is that "64-bit UEFI" is not an option for my scenario because dev/sda1 is too small and /dev/sda2 is ext2. Am I correct???
Second, assuming that "PC BIOS" was my only option, I put 'GRUB_PLATFORMS="pc"' in /etc/portage/make.conf and then -- after the usual mounting and chroot -- I proceeded with | Code: | | (chroot) livecd / # emerge sys-boot/grub:2 |
and then | Code: | (chroot) livecd / # grub-install /dev/sda
grub-install: error: /usr/lib/grub/x86_64-efi/modinfo.sh doesn't exist. Please specify --target or --directory. |
I suppose the error is not unsurprising because | Code: | (chroot) livecd / # ls /usr/lib/grub/
i386-pc |
Comparing with an old system I get a different result, | Code: | dpaddy # ls /usr/lib/grub/
i386-pc x86_64-efi |
so it looks like /usr/lib/grub/x86_64-efi is missing hence the error messge. Moreover, the old system I compare with boots fine and | Code: | dpaddy # parted /dev/sdb
GNU Parted 3.2
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) unit mib
(parted) print
Model: ATA WDC WD1005FBYZ-0 (scsi)
Disk /dev/sdb: 953870MiB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1.00MiB 9.00MiB 8.00MiB grub bios_grub
2 9.00MiB 1027MiB 1018MiB ext2 boot boot, esp
3 1027MiB 33795MiB 32768MiB linux-swap(v1) swap
4 33795MiB 953869MiB 920074MiB ext4 rootfs
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so the partitioning scheme on the old system seems the same... After reading the man page for grub-install I proceeded with | Code: | (chroot) livecd / # grub-install --target=i386-pc /dev/sda
Installing for i386-pc platform.
Installation finished. No error reported. |
My question here is: is there a miss-match between "Installing for i386-pc platform" and "x86_64 AMD Ryzen 7 1800X", and if so what consequences (performance, future software install/upgrade headaches,...) might I suffer and so should be aware of if I proceed from here???
Third, if I don't get potential problems sorted out here, then when I later attempt to upgrade/update the old system (X370 taichi motherboard) and if I follow the same path am I headed for trouble???
I suppose a summary would be that I feel ignorant and unconfident at this point and would appreciate guidance from someone who really knows what is going on 
Last edited by dpaddy on Fri Sep 04, 2020 7:46 pm; edited 1 time in total |
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NeddySeagoon
Administrator
Joined: 05 Jul 2003
Posts: 54300
Location: 56N 3W
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| Posted: Thu Sep 03, 2020 8:23 pm Post subject: |
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dpaddy,
You have a number of choices. I'll try to explain a little.
Mixing BIOS Booting and GPT is getting harder as the legacy BIOS option is not well tested and BIOS vendors are not interested in fixing it.
Use UEFI mode if at all possible. Starting with your partition table.
| Code: | Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1.00MiB 9.00MiB 8.00MiB grub bios_grub
2 9.00MiB 1027MiB 1018MiB ext2 boot boot, esp
3 1027MiB 33795MiB 32768MiB linux-swap(v1) swap
4 33795MiB 953869MiB 920074MiB ext4 rootfs |
Its GPT, not DOS. Good. UEFI booting only works with GPT.
| Code: | Number Start End Size File system Name Flags
1 1.00MiB 9.00MiB 8.00MiB grub bios_grub |
The bios_grub partition is used by grub. Its not yours, it does not appear in /etc/fstab.
Further, grub only uses it when you BIOS boot an a HDD that uses GPT. For you its going to be wasted space.
| Code: | Number Start End Size File system Name Flags
2 9.00MiB 1027MiB 1018MiB ext2 boot boot, esp |
This is your /boot, if you have a separate /boot partition and your esp too.
Regardless of the filesystem type in the partition table, it must actually be formatted vfat. That's the only filesystem that EFI can read and its going to load grub for here.
If its not already vfat, save the contents somwhere, reformat it then restore the content.
vfat does not support symbolic links.
| Code: | Number Start End Size File system Name Flags
3 1027MiB 33795MiB 32768MiB linux-swap(v1) swap
4 33795MiB 953869MiB 920074MiB ext4 rootfs |
That's conventional.
| dpaddy wrote: | | First, whereas I think there are both "PC BIOS" and "64-bit UEFI" options for the "GRUB_PLATFORM" (I am x86_64 AMD Ryzen 7 1800X) my muddled understanding is that "64-bit UEFI" is not an option for my scenario because dev/sda1 is too small and /dev/sda2 is ext2. Am I correct??? |
That's correct if its true. The partition type in the partition table need not reflect reality.
What does or say it is?
Proceed on the basis that you will use 64-bit UEFI.
| Code: | (chroot) livecd / # grub-install --target=i386-pc /dev/sda
Installing for i386-pc platform.
Installation finished. No error reported. |
Has installed grub for BIOS booting.
Does your motherboard firmware support that?
It will be called something like Legacy Mode.
If it does, it may just boot. If not, you need to go down the 64-bit UEFI path.
| dpaddy wrote: | | I suppose a summary would be that I feel ignorant and unconfident at this point and would appreciate guidance from someone who really knows what is going on |
Welcome to the club. That feeling never goes away. I've been playing with computers for well over 50 years. It gets replaced by the confidence to try things and back out those that don't work.
_________________
Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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dpaddy
Tux's lil' helper
Joined: 25 Jun 2008
Posts: 142
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| Posted: Fri Sep 04, 2020 7:45 pm Post subject: |
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O.K. so I've tried to go UEFI but I can't boot... after showing the uuid of the correct disk i see "not a valid root device".
Assuming that I've botched the kernel I will crawl through make menuconfig and rebuild.
I've never made UEFI boot before so am less than confident (not quite true, the rescue usb -- which I did not build -- boots UEFI).
I'll mark this "SOLVED" and open a new thread with details asking for advice when I inevitably fail. |
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dpaddy
Tux's lil' helper
Joined: 25 Jun 2008
Posts: 142
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| Posted: Fri Sep 04, 2020 9:32 pm Post subject: woot |
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The kernel was my problem; useful in that regard (when booted from rescue USB) was | Code: | | # lspci -v | sed -n -e '/Kernel driver in use:/p' |
All good now  |
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